914 Valve Cover
Modification

Difficulty Level 3

Difficulty scale:
Adding air to your tires is level one
Rebuilding a 911 Motor is level ten

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 6a

PROBLEM: Oil leaks past the cork valve cover gaskets and causes smoking at high RPMs and/or puddles of oil in the driveway when parked. This can be caused by several things all related to the gaskets moving: The gaskets getting old and stiff and the sealer coming loose, installing new gaskets with no sealer and they fall into the rocker area, loose bale wire that lets the gasket move or finally excessive blow by that pressurizes the valve cover and just overloads the vent system. These leaking gaskets can result in the “mysterious oil on top of the head under the intake manifold” leak that we see some times.

SOLUTIONS: There are several possible fixes: First is using a good hi temp sealant and making sure the bale wire is tight, which is about the lowest cost of all. I use the copper-based sealant and coat all four sides of the gasket before installing. I also let the sealant dry before using the engine although this is not always possible if the leak starts at a race and you want to keep running. Next is the alloy bolt-on style valve cover with the ridges to keep the gasket in place, but the problem here is the cost and the larger size of the covers on my 914 requires me to lower the engine to remove them. This may be due to the suspension reinforcements that reduce the side clearance of the engine. Finally is the possibility of modifying the stock valve covers to add a metal strip around the inside of the gasket to hold it in place. This is the solution I finally settled on after having the sealant start leaking at a race recently.

MODIFICATION STEPS:

1.    Jack up the rear of the car and support on jack stands.

2.    Remove the rear wheels, while this is not necessary it gives an old guy like me more room to get around under the car.

3.    Remove the vent line on each valve cover, if there is one. Check the hose for cracks or stiffness and replace as necessary. See Figure 1.

4.    Put some rags under the valve cover and remove it. Check to see if the bale wire is tight and if it is loose, you can remove it and bend slightly to cause it to press tighter on the valve cover. The bale fits into small holes at each end of the head. See Figure 2.

5.    Remove the old gasket and all sealer and clean the area well with solvent and a wire brush. Clean all oil from the valve cover since we will be welding here shortly.

6.    Cut some strips of 24 ga. Steel approximately 5/8 inch wide to weld inside the valve cover which will act like extensions of those two little tabs that are already installed. See Figure 3.

7.    Scuff the area with sand paper and bend the metal strips to fit and then clamp with a pair of welding pliers. Adjust the position so the cork gasket fits snugly all the way around. See Figure 4.

8.    Set the MIG welder to a low amperage setting (don’t want burn holes here) and make short tack weld every 1 inch or so. See Figure 5.

9.    Repeat for each valve cover until the strips are completed. See Figure 6.

10.    No painting will be necessary as this area will be covered with oil and should never corrode.

11.    Here is the time you can do a valve adjustment if necessary.

12.    Clean the gasket area with solvent and dry well. Make sure there are small pieces of weld metal sticking to the inside of the valve cover.

13.    Test fit the valve cover and bend the new tabs as necessary to allow the cover to fit snugly but have full contact with the seating surface of the head.

14.    Use the sealant of you choice and install a new gasket and then reinstall the modified valve cover. See Figure 6a.

15.    Make sure the bale wire is tight, bend as necessary for a snug fit.

16.    Reattach the vent hose if your engine is equipped with one, reattach the wheels and lower the car.

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